Control system



July 6, 1943. J. F. TRITLE 2,323,737

CONTROL SYSTEM Filed Aug. 9, 1941 Flrgt. Positwn Inventor: John .F Tritle;

H 5 Attofne g.

Patented July 6, 1943 UNITED STTES OFFICE CONTROL SYSTEM John F. Tritle, Erie, Pa., assignor to General Electric Company, a corporation of New York 8 Claims.

My invention relates to cam actuated control systems, more particularly to cam actuating mechanisms for such control systems. My invention is especially useful for simultaneously operating the throttle valves of a plurality of internal combustion engines in a manner which will insure proportional engine outputs over a predetermined range of control positions.

In power systems which comprise a plurality of internal combustion engines connected to drive a common load, as for example in multiple-engine Diesel-electric locomotives, it is customary to control the throttle valves of all the engines simultaneously by means of a single manually operable lever. Slight differences in engine characteristics make it necessary to provide individual adjustments between each throttle Valve and the manually operable control lever in order to insure that each engine carries its proper proportional amount of load throughout substantially the entire range of operation. To insure best results multiple-position adjustments for the throttle valve of each engine is desirable.

Accordingly, one object of my invention is to provide a cam actuated synchronous control system for the throttle valves of a plurality of internal combustion engines which shall be adjustable to insure proportional engine outputs over a wide range of control positions.

It is a further object of my invention to provide a cam actuated control system for a plurality of internal combustion engine throttle valves which shall be simple and inexpensive to manufacture while providing a three-position adjustment thereby to insure substantially synchronous control of the engines over substantially their entire range of operation.

.It is a still further object of my invention to provide a cam actuated mechanism capable of separate adjustment at a plurality of points and, accordingly, particularly suitable for use in synchronous control systems comprising a plurality of such mechanisms connected for simultaneous actuation by a single control member. By means of my adjustable cam mechanism, in equalities in the controlled elements to be moved synchronously may be compensated by independent multipoint adjustment of each of the actuating cams.

To the attainment of the above and other objects and advantages, my invention preferably comprises a plurality of adjustable cams and cam followers, each arranged to control the throttle valve of one of a plurality of connected internal combustion engines. Each adjustable cam includes a rotatable cam body connected to a common manually operable control lever and having pivotally mounted thereon a pair of oppositely extending cam lobes forming a continuous tracks way for a cam follower. The cam lobes are provided with means for maintaining their extending ends in following engagement with an ad justable set screw mounted upon the cam body, thereby to permit independent adjustment of each pivoted lobe with respect to the cam body. To provide an initial adjustment each cam follower is connected to its associated throttle valve by a connecting rod adjustable in length.

My invention itself will be better understood, however, and its objects and advantages further appreciated by referring now to the following detailed specification taken in connection with the accompanying drawing in which Fig. l is a schematic diagram of an internal combustion engine control system embodying my invention in one form; Fig. 2 is an enlarged side elevation of one of the adjustable cams and its followers as shown at Fig. 1; Figs. 3 and l are end and plan views respectively of the cam and follower shown at Fig. 2; and Fig. 5 is a fragmentary side view similar to that of Fig. 2 showing a device embodying my invention in a modified form.

Referring now to the drawing, I have shown at Fig. 1 a pair of internal combustion engines l0 and l I having throttle arms l2 and [3 which are biased to Valve closing position by tension springs It and E5 respectively. For operation of the throttle arms l2 and I3 a single manually operable throttle control lever 16 is connected to a control shaft I? to which are also connected a pair of rotatable cam bodies l8 and I9. Upon each cam body is pivotally mounted a pair of adjustable cam lobes 25, 26 having arcuate cam surfaces which form a continuous trackway for a cam follower 27. Each cam follower 21 is connected by means of a rod 28 of adjustable length to one of the throttle levers l2 and I3.

Referring now more particularly to Figs. 2, 3 and 4, I have shown in detail the structure of my adjustable cam and associated follower. Taking for example the cam having a body portion l8, the cam body is connected to a pin 30 which is rotatably mounted. in a bushing 3i mounted upon a base 32. The pin 35 may be slotted to form a keyway 39a thereby to facilitate connection to the control shaft ii. The cam body I8 is formed to provide a hub portion 33 and two side plates 34 and 35 extending from one side of the hub in parallel spaced relation. The cam body is solid in the region of the hub 33 to receive a set screw til intermediate the side plates 34 and 35. The

cam body i3 is also solid at its far end to provide means for mounting a second adjustable set screw M. In order to form a continuous trackway for the cam follower 21 the oppositely extending cam lobes 25, 26 are pivotally mounted in overlapping relation upon a pin 42 extending between the side plates 34 and 35. The cam lobes 25 and 26 are preferably biased into following engagement with the set screws 40 and 41, respectively, by means of a tension spring 43 connected between the extending ends of the cam lobes. In order to insure permanence of adjustment, the set screws 40 and ll are provided with lock nuts 45 and 45, respectively.

The cam follower 21 has a bifurcated end 58 carrying a cam roller and is integrally formed with an outwardly extending arm 52 which is connected to the adjustable rod 28. The follower 27 and the arm 52 extend from the same side of a hub 53 which is pivotally connected to l the base 32 by means of a bolt 52.

Individual adjustment of the throttle levers l2 and [3 may be obtained at a central and both end positions of the throttle control lever it in the following manner. speeds at the same point for the first running position of the throttle control lever IS, the operating mechanism is placed in the position shown in the drawing and the turnbuckles 29 are adjusted to obtain the desired engine speeds. Adjustment must be obtained by means of the turnbuckle in this position because of the fact that the rollers 5i are closely adjacent the pivot pins 22 where the cam surfaces are substantially nonadjustable. The idling position of the mechanism will ordinarily be that in which the roller 55 lies approximately halfway between the first position shown and the extreme right-hand end of the cam 25. Therefore, to set the idling speed of the engine, the mechanism is moved until the rollers come to this position and the set screws ii are adjusted to give the desired idling speeds. Likewise, a full speed adjustment may be obtained by rotating the throttle control lever IS and the cam bodies [8 and I9 until the rollers 5! lie near the left-hand end of the cam lobes 25. With the mechanism in this position, the set screws 45 are adjusted to give the desired full speed of the various engines. The outer extremity of the cam lobe 26 will now provide an off position in which the engines will be shut down.

It has been found that when all the cam lobes and all the cam lobes 25 are of identical shape, the three adjustments explained above will sufiiciently compensate for whatever slight difierences ordinarily exist in the characteristics in the same type of engine. Different types of engines, however, may require changes in the contour of the cam lobes 25 and 25.

To insure shutting down of all the engines when the control mechanism is in its ofi position, the more fully adjustable modification illustrated at Fig. 5 may be found preferable. In the arrangement according to Fig. 5, the shutting down of both engines when the mechanism is in its idling position is assured by an additional idling adjustment provided at the outer extremity of the cam lobe 26.

Referring now to Fig. 5, it will be observed that fundamentally the arrangement is similar to that shown in Fig. 2 and that corresponding parts have been assigned like reference numerals. In the modified form of my invention, however, the shut-off portion of the cam surface at the outer end of the cam lobe 25 is provided by an auxiliary In order to set the engine pivot pin GI.

shut-down cam lever 60 which is pivotally mounted upon the cam lobe 26 by means of a The pivot pin BI is preferably positioned relatively near to the shut-ofi portion of the cam lobe 26 so that adjustment of the shut-down lever will affect only the off position of the cam follower 27. For example, the pivot pin 6| may be located at or closely adjacent the idle portion of the lobe 26, as has been indicated at Fig. 5. The shut-down cam lever may be adjustably positioned with respect to the cam lobe 25 by means of a set screw 62 mounted at the outer end of the cam lob 26 and arranged to engage the outer end of the cam lever 60. The said screw 52 may be firmly fixed in any predetermined position by means of a locknut 63. To insure following engagement of the cam lever 60 with the said screw 52 a small tension spring 64 may be connected between the cam lobe 26 and the cam lever 60.

While I have shown but one prepared embodiment of my invention, many modifications will undoubtedly occur to those skilled in the art, and I, therefore, wish to have it understood that I intend by the appended claims to cover all such modifications which fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A cam-actuated mechanism comprising in combination, a movable member, a cam follower, adjustable means for connecting said follower to move said member throughout a limited range of movement, an adjustable cam operable in conjunction with said follower and comprising a pair of lobes pivoted together at a point defining an intermediate position in said range, said intermediate position being adjustably determinable by said adjustable means, means for independently adjusting one of said lobes about said point adjustably to determine a first limiting position of said range, and means for independently adjusting the other of said lobes about said point adjustably to determine the other limiting position of said range.

2. In a synchronous control system for a plurality of cam-actuated movable members of the type comprising a plurality of similar cam mechanisms connected to a single control member for simultaneously actuating each of said movable members throughout a limited range of movement, a cam mechanism comprising a cam follower, adjustable connecting means between said cam follower and one of said movable members, an adjustable cam in engaging relation with said follower and including a pair of lobes pivoted together at a point defining an intermediate position in said range, said intermediate position being adjustably determinable by adjustment of said connecting means, said lobes having arcuate cam surfaces co-acting to form a continuous trackway for said follower, means for independently adjusting one of said lobes about said point adjustably to determine a first limiting position of said range, and means for independently adjusting the other of said lobes about said point adjustably to determine the other limiting position of said range.

3. A cam-actuated mechanism comprising in combination, a movable member, a cam follower operatively connected to move said member throughout a range of movement, an adjustable cam operable in conjunction with said follower and comprising a rotatable cam body, a pair of ad ustable lobes pivotally mounted upon said cam body to form a continuous trackway for said follower, adjusting means mounted upon said cam body for engagement with said lobes, and means for retaining said lobes in following engagement with said adjusting means.

4. In a synchronous control system for a plurality of cam-actuated movable members of the type comprising a plurality of similar cam mechanisms connected to a single control member for simultaneously actuating each of said movable members throughout a limited range of movement, a cam mechanism comprising a rotatable cam body, a pair of adjustable cam lobes pivotally mounted upon said cam body to form a continuous trackway, set screws mounted in said cam body to engage the extending ends of said cam lobes, spring means connected between the extending ends of said lobes to retain said lobes in following engagement with said set screws, a pivoted cam follower biased into following engagement with said trackway, and adjustable means for connecting said follower to one of said movable members.

5. A cam-actuated mechanism comprising in combination a rotatable cam body, a pair of oppositely extending cam lobes pivotally mounted in overlapping relation upon a pin carried by said cam body thereby to form a continuous cam surface, a pair of set screws mounted upon said cam body, said set screws engaging the extending ends of said cam lobes, a tension spring connected between said extending ends of said lobes to bias said lobes into following engagement with said set screws, a cam follower lever biased into following engagement with said cam surface, and an actuating rod of adjustable length for connecting said follower lever to said movable member.

6. In a synchronous control system for a plurality of cam-actuated movable members of the type comprising a plurality of cam mechanisms connected to a single control member for simultaneously actuating each of said movable members throughout a limited range of movement, a cam mechanism comprising a rotatable cam body, said cam body comprising a pair of side plates in parallel spaced relation connected together to form a hub portion at one end thereof, a base plate providing bearing means for pivotally mounting said cam body, a pair of oppositely extending cam lobes pivotally mounted in overlapping relation upon a pivot pin carried by said cam body, said cam lobes forming a continuous cam surface, a pair of set screws mounted upon said cam body for engagement with the extending ends of said cam lobes, a tension spring positioned between the spaced side plates of said cam body and connecting said extending ends of said cam lobes thereby to bias said extending ends into following engagement with said set screws, a cam follower lever pivotally mounted upon said base to engage said cam surface, means for biasing said cam follower lever into continuous following engagement with said cam surface, and an actuating rod provided intermediate its ends with an adjustable turnbuckle for connecting said follower lever to one of said movable members.

7. A cam-actuated mechanism comprising in combination a movable member, a cam follower operatively connected to move said member throughout a range of movement, a rotatable cam body, a pair of oppositely extending adjustable lobes pivotally mounted upon said cam body to form a continuous trackway for said follower, adjusting means mounted-upon said cam body to engage each of said lobes, means for retaining said lobes in following engagement with said adjustin means, an auxiliary cam lever pivotally mounted upon said extending end of one of said cam lobes to form one end portion of said continuous trackway, and means for adjusting the position of said cam lever with respect to said one cam lobe adjustably to determine one limit of said range of movement.

8. A cam-actuated mechanism comprising in combination a movable member, a cam follower, adjustable means for connecting said follower to move said member throughout a limited range of movement, a rotatable cam body, a pair of adjustable cam lobes pivotally mounted upon said' cam body at a point defining an intermediate position in said range, said intermediate position being adjustably determinable by said adjusting means, said lobes extending in opposite directions from said point to provide a continuous trackway for said follower, adjustable means for individually positioning said lobes with respect to said cam body thereby adjustably to determine positions in said range between said intermediate position and the limits of said range, an auxiliary cam lever pivotally mounted upon the extending end of one of said cam lobes to provide a range limiting portion of said trackway, and means mounted upon said one cam lobe for adjustably positioning said cam lever with respect to said one cam lobe thereby adjustably to determine one limit of said range of movement independently of all other positions within said range.

JOHN F. TRITLE. 

